function y=lingyi(k)
if k==1
    y=[0;1];
else if k>1
        lc=2^(k-1);
        xinlie1=zeros(lc,1);
        xinlie2=ones(lc,1);
        xinlie=[xinlie1;xinlie2];
        pre_lingyi=lingyi(k-1);
        pre_lingyi=[pre_lingyi;pre_lingyi];
        y=[xinlie,pre_lingyi];
    end
end
end